Not Applicable
Not Applicable
The invention relates to materials testing systems, and more particularly to frictionless suspending in materials testing systems.
It is an important object of the invention to provide a materials testing system having an improved suspension.
According to the invention, a materials testing device for applying force to a test specimen includes a linear motor which includes an armature assembly which is mechanically coupleable to the test specimen, and a stator assembly. The materials testing device further includes a suspension for supporting the armature and for controlling the motion of the armature relative to the stator and to the test specimen, the suspension being arranged and constructed to operate without sliding contact between the armature assembly and the suspension.
In another aspect of the invention, a materials testing device includes a core of low reluctance magnetic material having two mutually opposing faces and an air gap separating the mutually opposing faces. A coil is wound around the core. A permanent magnet assembly is positioned in and substantially fills the air gap in noncontacting relationship with the core. The materials testing device further includes a frictionless flexural suspension structure for supporting the permanent magnet assemblPy and for controlling the direction of motion of the permanent magnet assembly.
In still another aspect of the invention, an electromechanical actuator assembly includes a structure of low reluctance material, a coil wound on the structure, the structure having substantially planar opposing faces. An air gap is between the opposing faces. A movable permanent magnet assembly having regions of opposite polarity is disposed in and substantially fills the air gap. The actuator assembly is characterized by three axes, a first of the axes perpendicular to the opposing faces, a second of the axes perpendicular to the first axis and between the regions of opposite polarity, a third of the axes perpendicular to the first axis and the second axis. A substantially frictionless suspension assembly supports the permanent magnet assembly. The suspension assembly has different stiffnesses along each of the three axes. The suspension is stiffest along the first axis.
Other features, objects, and advantages will become apparent from the following detailed description, which refers to the following drawings in which: